[PowerPC] Fix machine verify pass error for PATCHPOINT pseudo instruction that bad machine code

[ZhangKang]

Summary

This patch to fix below patchpoint error when using verify-machineinstrs option:

*** Bad machine code: Using an undefined physical register ***
- function:    test
- basic block: %bb.0 entry (0x1002e0ed008)
- instruction: PATCHPOINT 0, 40, 0, 2, 13, killed %1:gprc, killed %0:gprc, 2, 3, <regmask $cr0 $cr1 $cr2 $cr3 $cr4 $cr5 $cr6 $cr7 $f0 $f1 $f2 $f3 $f4 $f5 $f6 $f7 $f8 $f9 $f10 $f11 $f12 $f13 $f14 $f15 $f16 $f17 $f18 $f19 $f20 $f21 $f22 $f23 $f24 and 93 more...>, implicit-def dead early-clobber $x12, implicit-def dead early-clobber $lr8, implicit-def dead early-clobber $ctr8, implicit-def $r1, implicit $x2
- operand 14:   implicit $x2

For SDAG, we pretend patchpoints aren't special at all until we emit the code for the pseudo.
Then the verifier runs and it seems like we have a use of an undefined register (the register will
be reserved later, but the verifier doesn't know that).

So this patch call setUsesTOCBasePtr before emit the code for the pseudo, so verifier
can know X2 is a reserved register.

[nemanjai]

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

5098 ↗

(On Diff #179688)

This condition is a never true if the previous one isn't. So this can be changed to just if (!isPatchPoint) and contained within the above if (isSVR4ABI && isPPC64).

[hfinkel]

So this rell-request

typo in the summary "rell"

[ZhangKang]

In D56148#1342250, @hfinkel wrote:

So this rell-request

typo in the summary "rell"

I have modified it.

[ZhangKang]

Put if (!isPatchPoint) within if (isSVR4ABI && isPPC64) to follow nemanjai's suggestion.

[ZhangKang]

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

5098 ↗

(On Diff #179688)

I have updated the patch to follow your suggestion.

[nemanjai]

LGTM.

llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp

PrepareCall(SelectionDAG &DAG, SDValue &Callee, SDValue &InFlag, SDValue &Chain,
   // Add argument registers to the end of the list so that they are known live
   // into the call.
   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
     Ops.push_back(DAG.getRegister(RegsToPass[i].first,
                                   RegsToPass[i].second.getValueType()));
 
   // All calls, in both the ELF V1 and V2 ABIs, need the TOC register live
   // into the call.
-  if (isSVR4ABI && isPPC64 && !isPatchPoint) {
+  // We do need to reserve X2 to appease the verifier for the PATCHPOINT.
+  if (isSVR4ABI && isPPC64) {
     setUsesTOCBasePtr(DAG);
+
+    // We cannot add X2 as an operand here for PATCHPOINT, because there is no
+    // way to mark dependencies as implicit here. We will add the X2 dependency
+    // in EmitInstrWithCustomInserter.
+    if (!isPatchPoint) 
       Ops.push_back(DAG.getRegister(PPC::X2, PtrVT));
   }
 
   return CallOpc;
 }
 
 SDValue PPCTargetLowering::LowerCallResult(
     SDValue Chain, SDValue InFlag, CallingConv::ID CallConv, bool isVarArg,
     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
if (MI.getOpcode() == TargetOpcode::STACKMAP ||
       MI.getOpcode() == TargetOpcode::PATCHPOINT) {
     if (Subtarget.isPPC64() && Subtarget.isSVR4ABI() &&
         MI.getOpcode() == TargetOpcode::PATCHPOINT) {
       // Call lowering should have added an r2 operand to indicate a dependence
       // on the TOC base pointer value. It can't however, because there is no
       // way to mark the dependence as implicit there, and so the stackmap code
       // will confuse it with a regular operand. Instead, add the dependence
       // here.
-      setUsesTOCBasePtr(*BB->getParent());
       MI.addOperand(MachineOperand::CreateReg(PPC::X2, false, true));
     }
 
     return emitPatchPoint(MI, BB);
   }
 
   if (MI.getOpcode() == PPC::EH_SjLj_SetJmp32 ||
       MI.getOpcode() == PPC::EH_SjLj_SetJmp64) {

llvm/trunk/test/CodeGen/PowerPC/ppc64-anyregcc-crash.ll

-; RUN: not llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: not llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 ;
 ; Check that misuse of anyregcc results in a compile time error.
 
 ; CHECK: LLVM ERROR: ran out of registers during register allocation
 define i64 @anyreglimit(i64 %v1, i64 %v2, i64 %v3, i64 %v4, i64 %v5, i64 %v6, i64 %v7, i64 %v8,
                         i64 %v9, i64 %v10, i64 %v11, i64 %v12, i64 %v13, i64 %v14, i64 %v15, i64 %v16,
                         i64 %v17, i64 %v18, i64 %v19, i64 %v20, i64 %v21, i64 %v22, i64 %v23, i64 %v24,
                         i64 %v25, i64 %v26, i64 %v27, i64 %v28, i64 %v29, i64 %v30, i64 %v31, i64 %v32) {

llvm/trunk/test/CodeGen/PowerPC/ppc64-anyregcc.ll

-; RUN: llc < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s
 target datalayout = "E-m:e-i64:64-n32:64"
 target triple = "powerpc64-unknown-linux-gnu"
 
 ; CHECK-LABEL: test:
 ; CHECK: {{^}}.L[[test_BEGIN:.*]]:{{$}}
 
 ; CHECK-LABEL: property_access1:
 ; CHECK: {{^}}.L[[property_access1_BEGIN:.*]]:{{$}}

llvm/trunk/test/CodeGen/PowerPC/ppc64-patchpoint.ll

-; RUN: llc                             < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-BE
-; RUN: llc -fast-isel -fast-isel-abort=1 < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-BE
-; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu                             < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-LE
-; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu -fast-isel -fast-isel-abort=1 < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-LE
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-BE
+; RUN: llc -fast-isel -fast-isel-abort=1 -verify-machineinstrs < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-BE
+; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu -verify-machineinstrs < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-LE
+; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu -fast-isel -fast-isel-abort=1 -verify-machineinstrs < %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-LE
 
 target triple = "powerpc64-unknown-linux-gnu"
 
 ; Trivial patchpoint codegen
 ;
 define i64 @trivial_patchpoint_codegen(i64 %p1, i64 %p2, i64 %p3, i64 %p4) {
 entry:
 ; CHECK-LABEL: trivial_patchpoint_codegen:

llvm/trunk/test/CodeGen/PowerPC/ppc64-stackmap.ll

-; RUN: llc                             < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s
 ;
 ; Note: Print verbose stackmaps using -debug-only=stackmaps.
 
 ; We are not getting the correct stack alignment when cross compiling for arm64.
 ; So specify a datalayout here.
 target datalayout = "E-m:e-i64:64-n32:64"
 target triple = "powerpc64-unknown-linux-gnu"